Secretary of State John Kerry signed the Arms Trade Treaty last week, which can be read here in its entirety. Humanitarian disarmament groups hail this as a victory. Guns rights groups call it a travesty.

Signing the treaty probably won’t matter much in legal terms for the United States. NYT editorial opinion aside, ratification is highly unlikely. The US is known for signing and not ratifying humanitarian treaties: international agreements to which it is (or was once) party in the dreams of the Executive Branch alone include the 1977 Additional Protocol to the Geneva Conventions, the Rome Treaty of the International Criminal Court, the Convention on the Rights of the Child and the Convention on the Elimination of Discrimination Against Women.

Yet signing a treaty is not a pointless exercise. (This is exactly why the White House doesn’t always do it – note the landmines and cluster munitions cases). It signals a support for the norms in the treaty and lip service toward aligning policy voluntarily with those norms. So regardless of whether the US will ever be bound by this treaty, one political implication is that the Obama Administration’s implicit commitment to the treaty norms will expose it to questions about its recent pledge to arm Syrian rebels. As bad as Assad may be, and as justifiable as support to the rebels may be depending on your perspective, it is an absolute fact that various rebel factions have engaged in behavior that, if the US armed them, would put the US in violation of Article 6(3) which reads:

A State Party shall not authorize any transfer of conventional arms covered under Article 2 (1) or of items covered under Article 3 or Article 4, if it has knowledge at the time of authorization that the arms or items would be used in the commission of genocide, crimes against humanity, grave breaches of the Geneva Conventions of 1949, attacks directed against civilian objects or civilians protected as such, or other war crimes as defined by international agreements to which it is a Party.